1. Field of the Invention
The instant disclosure relates to a motion detecting device; in particular, to motion detecting device for dynamically adjusting an image sensing region.
2. Description of Related Art
With rapid development of the technology, it brings the wide application of the computer. A mouse serves as an input tool of a computer, which greatly facilitate the operation of the computer in people. In operation, when the mouse is placed on a mounted platform, it can control cursor pointer of computer by moving the mouse on the mounted platform. With the continuous upgrading of electronic products, demands for electronic products have become increasingly high by the consumer. To enhance the convenience of use for computer equipment, a traditional wired mouse has gradually replaced by a wireless optical mouse. The wireless optical mouse typically includes a light source, a digital signal processor, an image sensor and a wireless transmission unit (i.e. energy-consuming elements), its overall energy consumption is large and the wireless optical mouse is with the problem of insufficient battery life.
The optical mouse in prior art utilizes the image sensor to capture reference images consecutively, and then compares a reference frame captured by the image sensor with a current frame in a sampling period so as to determine an amount of the displacement. After determining the amount of the displacement, the current frame is updated as the reference frame and then the optical mouse in prior art compares the reference frame updated with the current frame newly captured so as to acquire another amount of the displacement in the next sampling period. However, the method for detecting displacement exist a problem of insufficient accuracy. Accordingly, a user is not able to make movement of the cursor move with higher speed. Moreover, the optical mouse includes the light source, the digital signal processor, the image sensor and the wireless transmission unit (i.e. energy-consuming elements), so total energy consumption for the image sensor is large.